Effects of Various Co-Dopants and Carbonates on the Properties of Doped Ceria-Based Electrolytes: A Brief Review

摘要

Solid oxide fuel cells (SOFCs) are the most efficient clean energy devices that directly convert fuel chemical energy to electricity. Traditional SOFCs operated under 800℃ to 1000℃ use yttria-stabilized zirconia (YSZ) as an electrolyte. This high temperature range limits the commercial use of conventional SOFCs. Resistive causes, such as expensive materials, thermal stress, and long start-up and shut-down times, also limit SOFC commercial use. In the last decade, research on SOFCs has focused on decreasing the operating temperature by developing novel materials, notably electrolyte materials with sufficient ionic conductivities. Doped ceria-based electrolytes demonstrate higher oxygen ion conductivity than YSZ, especially at low temperatures. Such electrolytes are also the most extensively studied electrolytes for SOFCs operating at 500℃ to 800℃. Two strategies have been adopted to obtain sufficient ionic conductivity in singly doped ceria electrolytes: the doping of some co-dopant ions and the addition of carbonates (Li_2CO_3 and Na_2CO_3) in singly doped ceria. This paper aims to provide a concise review and outlook of various co-doped and composite electrolytes based on doped ceria and synthesized through various routes. The effects of different co-dopants and carbonates on the electrical properties of doped ceria-based electrolytes are also reviewed and discussed.